Depends what you want to do.
If you use primarily discs to run your games (rather than USB) then a modchip is advantageous. If you have other people around who might update your Wii either from disc or internet then a modchip is advantageous. if you think you might be installing lots of bad wad files then a modchip can help you recover from a brick.
Backup loaders are limited to 3x speed to you might see stuttering on video, this is overcome by USB loaders.
I'm glad I got mine but not sure if I'd buy another, if I bought a second Wii.